1835, from earlier Lynch law (1811), likely named after William Lynch (1742-1820) of Pittsylvania, Virginia, who c.1780 led a vigilance committee to keep order there during the Revolution. Other sources trace the name to Charles Lynch (1736-1796) a Virginia magistrate who fined and imprisoned Tories in his district c.1782, but the connection to him is less likely. Originally any sort of summary justice, especially by flogging; narrowing of focus to "extralegal execution by hanging" is 20c. Lynch mob is attested from 1838. The surname is perhaps from Irish Loingseach "sailor." Compare earlier Lydford law, from a place in Dartmoor, England, "where was held a Stannaries Court of summary jurisdiction" [Weekley], hence:

Lydford law: is to hang men first, and indite them afterwards. [Thomas Blount, "Glossographia," 1656]

mid-14c., from Latin lynx (source of Spanish, Portuguese, Italian lince), from Greek lyngz, perhaps from PIE *leuk- "light" (see light (n.)), in reference to its gleaming eyes or its ability to see in the dark.

If that men hadden eyghen of a beeste that highte lynx, so that the lokynge of folk myghte percen thurw the thynges that withstonden it. [Chaucer's "Boethius," c.1380]

Compare Lithuanian luzzis, Old High German luhs, German luchs, Old English lox, Dutch los, Swedish lo "lynx."

"a lyric poem," 1580s, from Middle French lyrique "short poem expressing personal emotion," from Latin lyricus "of or for the lyre," from Greek lyrikos "singing to the lyre," from lyra (see lyre). Meaning "words of a popular song" is first recorded 1876. Related: lyrics.